On Thursday, the IP address of forums.debian.net needs to change. This change will happen during the Western-European morning, i.e., 8:00 UTC - 11:00 UTC.

I hope this change can be performed quickly, but I know some DNS servers of some ISP's disregard time-outs (TTL's) on hostnames, and will cache any IP address for 24h, even though it is indicated they should check more often.